Eclampsia is pregnancy-related seizure activity that is usually caused by severe preeclampsia (a pregnancy complication). Eclampsia is a life-threatening condition for both a mother and her fetus. During a seizure, the oxygen supply to the fetus is drastically reduced.

Less than 1% of women with preeclampsia experience seizures. Sudden eclampsia can occur before, during, or (rarely) up to 6 weeks after delivery. Seizures that do occur after delivery (postpartum seizures) are most common during the first 48 hours after delivery.

Magnesium sulfate treatment is a highly effective prevention and treatment for eclampsia. It is typically given to high-risk women during labor and for 24 hours after delivery and to women having an eclamptic seizure.